从异步错误转移到异步真 [英] moving from async false to async true

问题描述

所以我有一张code运行了好几次

Hi so I have a piece of code that run quite a few times

Loader.load（数据/ map.json'）

Loader.load('data/map.json')

的想法是，我可以传递任何JSON文件加载程序将处理它

the idea is I can pass in any json file and the loader will deal with it

所以这里是异步错误格式的加载器

so here is the loader in async false format

  var Loader = {
    basePath: '',
    cache: {},
    load: function(name) {
        if(typeof this.cache[name] == 'undefined') {
            var loadUrl = (this.basePath == '') ? name : this.basePath + '/' + name;
            var parameters = {

                url: loadUrl,
                dataType: 'json',
                async: false,
                context: this,
                success: function(data) {
                    this.cache[name] = data;
                }
            };

            $.ajax(parameters);
        }
        return this.cache[name];
   }
};
return Loader;

但这是异步假的格式，我需要得到这个异​​步真正的格式与jQuerymobile更好的工作，所以对这里的一些帮助，我设法得到它的一个点，它的异步

but this is in async false format and I need to get this to async true format to work better with jQuerymobile so with some help on here I managed to get it to a point where its async

var data = AsyncLoader.load('data/map.json').done(function(data, textStatus, jqXHR) {
            console.log("complete");

        }).fail(function(jqXHR, textStatus, errorThrown) {

            console.log("an error has occurred");

        }).always(function(jqXHR, textStatus) {
            console.log("running");
        });

此调用的asynloader

this call the asynloader

function($) {
var AsyncLoader = {
    basePath: '',
    cache: {},
    load: function(name) {
        if(typeof this.cache[name] == 'undefined') {
            var loadUrl = (this.basePath == '') ? name : this.basePath + '/' + name;
            var parameters = {
                beforeSend: function() { $.mobile.showPageLoadingMsg(); },
                complete: function() {$.mobile.hidePageLoadingMsg(); },
                url: loadUrl,
                dataType: 'json',
                async: true,
                context: this,
                success: function(data) {
                    this.cache[name] = data;
                }
            };

            $.ajax(parameters);
        }

        return this.cache[name];
    }
};

return AsyncLoader;

问题是使这项工作我需要返回$阿贾克斯（参数），而不是返回this.cache [名]否则，我得到一个JavaScript错误......问题是，如果我改变它获得$阿贾克斯（参数），当我在maps.json加载第二次它不会从this.cache它会加载数据JSON文件又是没用的。

the problem is to make this work I need to return $.ajax(parameters) rather than return this.cache[name]; otherwise I get a javascript error.. the problem is if I change it to get $.ajax(parameters) when I load in maps.json for a second time it doesn't get the data from the this.cache it will load the json file again which is useless

谁能帮助

感谢：）

推荐答案

$。阿贾克斯返回的一个延迟对象。你也可以回到自己的延迟对象。你的新的code可能看起来有点像这样的：

$.ajax returns a Deferred object. You, too, can return your own Deferred object. Your new code might look a little like this:

load: function(name) {
    // Is the object already in the cache?
    if(Object.prototype.hasOwnProperty.call(this.cache, name)) {
        // Yes! Return a Deferred that's already been resolved.
        return jQuery.Deferred().resolve(this.cache[name]);
    }else{
        // No! We have to load it. Let's still use our own Deferred, though:
        var deferred = jQuery.Deferred();

        // There's our Deferred. Now let's load it.
        jQuery.ajax({
            // ...
        }).done(function(data) {
            // We loaded it successfully!
            // Add it to our cache and resolve the Deferred.
            this.cache[name] = data;
            deferred.resolve(data);
        }).fail(function() {
            // Fail! Pass the failure on to our deferred.
            deferred.reject.apply(deferred, arguments);
        });

        // We've started the AJAX request. Now return our Deferred.
        return deferred;
    }
}

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